Over the past decade, the number of teen drivers ages 15 to 17 involved in a fatal accident has decreased by 60 percent, according to a study conducted by the Texas A&M Transportation Institute, falling from 2,832 to 2002 to 1,134 in 2011.
But here's the concerning news: Passengers are increasingly harmful to teen drivers. Even as the overall number of crash deaths dramatically dropped, the risk has dramatically increased for the same teen drivers if they are carrying passengers.
The same novice drivers, ages 15 to 17, are eight times more likely to be involved in a fatal crash than those just a little bit older, ages 18 to 24, if they are also carrying teen passengers, according to TTI research. That risk has increased 30 percent over the past decade.
Researchers focused on the numbers and not the underlying causes that might be behind the dramatic and contrasting shifts. But they note the spike in fatal crashes for teens carrying passengers essentially mirrors the spike in cell phone use and texting as a central part of teen culture.
"We can't scientifically state that there's a direct link between those two things yet, but it seems reasonable to suspect a connection," said Russell Henk, a senior research engineer at TTI and primary author of the study.
Inexperience is one reason teens find themselves in such high-risk driving situations. Another reason the teens in the 15 to 17 age bracket might be so much more likely to be involved in fatal accident compared to those 18 to 24 has to do with their brain development.
The prefrontal cortex region of the brain, which controls risk assessment and decision making, is not fully developed until age 25, researchers said.
"That helps to explain why some teens are a bit more impulsive and prone to risk taking," says Bernie Fette, another researcher involved with the TTI study. "Those 15 or 16 year olds, they've got an awful lot of things fighting against them behind the wheel."
"Those 15 or 16 year olds, they've got an awful lot of things fighting against them behind the wheel."
If physiological development helps explain part of the difference between drivers ages 15 to 17 and those in the 18 to 24 age bracket, there's another aspect that remains puzzling. The difference in risk between the two age brackets can vary greatly depending on location.
For example, in New York, the younger teens are comparatively safer; their risk of being involved in a fatal crash is only five times that of the 18- to 24-year-olds when passengers are in the car.
But in North Carolina, the risk is far higher. Teens ages 15 to 17 are 26 times more likely to be involved in a fatal accident with passengers than those in the 18 to 24 age bracket.
Pete Bigelow is an associate editor at AOL Autos. He can be reached via email at firstname.lastname@example.org and followed on Twitter @PeterCBigelow.